1. Field of the Invention
The present invention relates to an orthodontic bracket and a clip release tool, and in particular, for correcting irregular teeth rows or twisted teeth, relates to an orthodontic bracket and a clip release tool.
2. Description of the Related Art
In general, the orthodontic bracket has been used for correcting teeth rows. As to the orthodontic bracket, a base thereof is provided with a bracket main body. The bracket main body is formed with an arch wire slot for receiving an arch wire therein and is furnished with a clip for preventing the arch wire from getting out from the interior of arch wire slot.
The clip is curved substantially in U-shape and is formed to be engageable in such a manner that a catching end portion formed at an upper distal portion of the clip creeps under a catching part of the bracket main body.
As means for taking off the upper distal portion of the clip from the catching part, the following technologies are disclosed.
For example, U.S. Pat. No. 4,698,017 shows an art of rotating a clip by a bar-like tool to release the arch wire slot.
U.S. Pat. No. 5,562,444 shows an art of releasing a clip rotating round a tie-wing by the bar-like tool inserted in a hole of the clip.
This publication also discloses a way of pushing to open the front end of the clip by use of a tool (not especially designated).
In addition, U.S. Pat. No. 5,906,486 is concerned with a self-ligation bracket of sliding a U-shaped clip and releasing and closing the arch wire slot, and shows an art of inserting the bar-like tool into the hole of the clip for releasing the clip.
The self-ligation bracket is meant by a bracket where an opening of the arch wire slot is closed with a rotating or sliding clip so that the arch wire does not get out from the interior of the arch wire slot.
But, when releasing the clip by the bar-like tool inserted in the hole of the clip, it is necessary to work the bar-like tool as a lever, and so an exceeding load is effected on the clip.
Therefore, when releasing the clip by the bar-like tool, the clip is often deformed.
In case the clip is deformed, even if returning the clip to a closing position, not only the deformed clip cannot press down the arch wire, but also the arch wire gets out of position not to continue a curing.
Further, since the hole into which the bar-like tool is inserted is formed at about center of the clip, a spring property of the clip is spoiled to reduce force pressing down the arch wire, and besides a problem arises that the clip is easily deformed owing to concentration of stress.